Transmission synchronizing mechanism



Nov. 2, 1943.v o. E. FISHBURN 2,333,165

TRANsMrssIQN sYNcHRoNIzINGIMEcHANIsM Filed Dec. 2o. 1957 s sheets-sheeti Nov. 2, 1943. o` E. FlsHBURN -l I TRANSMISSION SYNCHRONIZING MECHANISMkFiled Dec. 2o, 1937 s sheets-sheet 2 l v VENTOR. O szcrp.

ATTORNEYS.

Nov. 2, 1943. i o. E. FlsHBuRN 2,333,165

TRANSMISSION SYNCHRONIZING MECHANISM Filed nec. 2 0, 1957 6 sheets-skins @JJ-L INVENTOR.

A TFORNEYSt Nov.. 2, 1943. o. E@ FlsHBURN 2,333,165

lTRNSMIS*SION SYNCHRONIZING MECHANISM Filed Deo. 2o, 1937 e sheeis-snet4 |H|| I- l L will,

Nov. 2, 1943. o. E. FlsHBURN TRANSMISSION SYNCHRONIZING MECHANISM FiledDec.. 20, 1937 6 Sheets-Sheet 5 0.322 Z' BY www Patented Nov. I' 2, 1943TRANSMISSION sYNcnnoNIzmG MECHANISM otto E. Fishbuni, Detroit, Mich.,assignor to Chrysler Corporation, Highland Park, Mich., a corporation ofDelaware l Application December Z0, 1937, Serial No. 180,840

56 Claims.

This invention relates to motor vehicle transmissions and. refers moreparticularly to unprovements in synchromesh mechanisms for use with suchtransmissions.

Fig. is a sectional elevational view taken along line 5 5 of Fig. 2.

Fig. 6 is a, fragementary sectional view along line 6 6 of Fig. 2.

This application is a continuation in part of 5 Fig. 6A is a detailedsectional view taken along my copending application Serial No. 108,123,filed line (iA-6A of Fig. 2, the opposite movements of October 29, 1936,now abandoned. one of the synchronizing ring teeth being shown Oneobject. of my invention is to provide an in dotted lines. l improvedmeans for. synchronizing the speeds of Fig. 6B is an enlarged plan viewof an end shafts preparatory to positively clutching the' 10 of theteeth of the shift collar.

shafts together, such means being of a positive Fig. 7 is a top planView of the synchromesh character and of a simple construction capableparts in their Fig. 8 positions, the teeth of the of long use withoutundue wear. shiftable collar being shown in cross section.

Another object of my invention is to provide Fig. 8 is a sectionalelevational view of. the a synchronizing device which will insureagainst synchromesh parts positions during the synchroclashing of theshiftable clutch teeth and which mesh engagement of second speed ratio.operates in a" minimum of time to control the Fig. 9 is a viewcorresponding to Fig. '7 with rotative speeds of the parts to beclutched; also the parts fully engaged for second speed ratio whichrequires very little effort to operate the drive. synchronizing parts inmanipulating the trans- Fig. 10 is a view corresponding to Fig. 8 butmission. showing the parts positioned as in Fig. 9.

An additional object is to provide an improved Fig.' 11 is a viewcorresponding to Fig. 7 but synchromesh mechanism which is positive inits illustrating the parts during the opposite shift control of thesynchronizing parts and which has movement of the collar for shiftinginto the a servo or self-energizing action in controlling direct drive.the speed ratio changing mechanism; also an im- Fig. -12 is an enlargedfragmentary sectional 'proved synchronizing mechanism which is bi- Viewof one of the friction cups as seen at the directional in its control ofthe parts to be extreme right of Fig. 3.

clutched regardless of which of these parts has Fig. 13 is a viewgenerally corresponding to the faster rotation at the start of theclutching Fig. 2 but illustrating a slightly modified form action. of myinvention. l

A further object of my inventionl is to provide Fig. 14 is a sectionalelevational View taken an improved synchromesh mechanism for transasindicated by line Ill-I4 of Fig. 13. mission gearing incorporating meansto brake Fig. 15 is a view generally corresponding to the spin of themain clutch driven parts when Figs. 2 and 13 but illustrating a furthermodificathe main clutch is disengaged, thereby faci1itat tion of myinvention. ing changes in the settings of thev transmission Fig. 16 is asectional elevational view taken including changes which do not have asynchroas indicated by line I6 |6 of Fig. 15. mesh mechanism especiallyprovided therefor. Fig. 17 is a fragmentary sectional elevationalFurther objects and advantages of my invenview showing a still furthermodication of my tion will be apparent from the following deinvention.scription of several embodiments of my inven- Fig. 18 is a viewgenerally corresponding to tion, reference being had to the accompanyingFigs. 2, 13 and 15 but showing an additional emdrawings in Which:bodiment of my invention.

Fig. 1 is a sectional elevational view through my v45 Figs. 19 and 20are sectional elevational views transmission illustrating my synchromeshmechtaken respectively as indicated by lines |9 |9 anism for the secondand direct driving ratios. and 2li-20 of Fig. 18.

Fig. 2 is anenlargedsectional elevational view Fig. 21 is a perspectiveview of the spreader of the synchromesh mechanism, a portion of thespring illustrated in Fig. 18.

Structure being in elevatiOrL Fig. 22 is a fragementary View of aportion of Fig. 3 is an exploded view of the shiftable the Fig. 18synchromesh mechanism but illussynchromesh parts with portions brokenaway to trating another form: of expansion ring. illustrate the interiorstructure. Referring to the drawings, I have illustrated Fig. 4 is asectional elevational view taken along my synchronizing mechanism inconnection with line 4 4 of Fig. 2.v 65 a motor vehicle transmission nowin general use although I desire to point out that my improvements areapplicable to other transmission. ar-

rangements and generally where it is desired to synchronize anddrivingly couple a pair yof rotating members. The conventionaltransmission illustrated in Fig. l comprises a driving shaft |5 which isadapted to be driven by the usual engine, preferably through the mediumof the well known main clutch, the engine and clutch not beingillustrated in my drawings as they may be of any well known form and.arrangement such as now used in motor vehicles.

The driving shaft |5 carries the main or primary driving gear |6 forrotation therewith, this gear being in constant mesh with the gear |1 ofthe countershaft gear cluster mounted for rotation on the countershaft|8. This gear cluster, according to well known practice, comprises a lowspeed gear I9, a second speed gear 2li, and

a reverse gear 2| which is in constant meshwith Vthe reverse idler gear22. The transmission driven shaft 23 extends rearwardly to drive theground wheels of the vehicle, the usual propeller shaft brake beingillustrated at 24 and the speedometer driving gears being illustrated at25.

The driven shaft 23 has mounted' thereon the low speed and reverse gear26 splined to the driven shaft for selective meshing with thecountershaft low speed gear I8 or the reverse idler gear 22 forrespectively transmitting a low speed drive to the driven shaft 23 orthe drive thereto in a reverse direction. Freely rotatable on shaft 23is the second speed or secondary gear 21 in constant mesh with vthecountershaft gear 20,

the principles of my invention being illustrated in connection withimproved means for selecrvtively drivingly connecting gears |'6 and 21with the driven shaft 23 for respectively transmitting thereto a directdrive or the second speed ratio drive as will be presently moreapparent. The transmission drives lmay be controlled generally accordingto customary practice by manual manipulation of the usual gear shiftleve 28 selectively engageable with the sliding rail mechanism 29'foractuating the yokes 30 and 3| to control the drives to gear 26 and thedrives in second and direct speeds. Referring particularly to Figi 2,the driven shaft .23 carries the usual splined ring 32 which preventsforward displacement of the driving gear 21 and forwardly adjacent thisring, shaft 23 is formed with splines 33 and' a forward end portion 34rotatably piloted'by the roller bearing urging a ball detent 45outwardly from the rim portion 46 of the hub. 'This rim portion axiallyoverhangs the radially extending body portion of the hub in oppositedirections and circumferentially between adjacent pockets 43 I have'formed the concave recesses or apertures 41. These r'esesses may beconveniently formed by a rotary cutting tool, it being noted that eachrecess 41 is sufficiently deep to cut through the rim Dortion' 418 atthe .iunctures of the body portion 42 `thereby forming the oppositelyextending openings or slideways at 48. Circumferentially of the rimportion 4S between each of the pockets 43 and the recesses 41, the rimportion is provided with a plurality of axially extending splines 49adapted to receive the circumferentially extendlng set of internalclutching teeth 50 carried by the shiftable synchromesh clutch collar 5|which is formed with the' annular groove 52 for receiving the aforesaidshiftable yoke 3| whereby the sleeve or collar 5| may be shifted axiallyforwardly or rearwardly to engage the clutching teeth 50 thereof withthe clutching teeth 38 or 36 respec- 1 tively. In Fig. 2 the collar 5|is in its neutral be clutched and means for preventinga completeshifting movement of collar 5| to engage teeth 86 or 38 until thesynchronizing relationship of the clutching teeth is established. 'I'hissynchron'izing and clutching controlling means comprises a synchronizingcontrol ring structure 54 having Va substantially cylindrical bodyportion formed with the axially projecting tongues 55 which enter theguideways 48 and extend into the respective recesses 41, thecircumferential width of each tongue 55 being substantially less thanthe corresponding width of the recesses 41 so that While the ring 54 isrotated with the hub 42, the ring is also capable of limited rotationrelative to the hub in opposite directions from the neutral condition orposition illustrated in Fig. 6. The ring 54 is also capable of limitedaxial movement relative to the hub 42, inward movement being limited bythe ring striking the hub .and axial outward movement being limited bythe cone 31 as will presently be more apparent.

35 within the rearwardly overhanging portion of the driving shaft I5 andgear I6. The gear 21 drivingly carries a set of circumferentiallyarranged external clutching teeth 36 and one element of a synchronizingfriction clutch preferably in the form of a cone 31. For convenienceof/manufacture it is preferred to form the driving cone 31 and clutchteeth 38 integrally with the body portion of gear 21. In similar manner,the gear I6 drivingly carries the corresponding set of clutching teeth38 and the driving cone 39. The forwardly extending edges of teeth 136are bevelled ortapered at 40 and the rear edges of .teeth 38 arecorrespondingly formed at 4|.

Mounted on i.the splines 33 for rotation with lshaft; 23 and forshifting movement axially thereof is the synchronizing clutchingmechanism comprising the following cooperating structural parts. Asynchronizing hub 42 engages the splines 33, this hub being formed witha plurality of circumferentially spaced outwardly opening pockets Ring54 carries the synchronizing driven friction clutch element 55 which isillustrated in the form of a bronze cup iixed to the ring by strikingcircumferentially space( portions thereof outwardly'at'51 into theradially extending openings 58 formed in ring 54. Theinner clutchingface of cup 55 has the general contour of' a portion `of a cone similarto the smooth surface of the companion clutching cone 31 and as one ofthe features of my improvements I have formed the clutching surface ofthe 'cup by cutting therein the threads 58 best shown in Fig. 12which'is a development about ten times actual size. In actual practice Ifind that approximately forty threads per inch will give good results inaccord- The ance with the objects of my invention. threads 58'arefurthermore preferably formed left handed and the angle of the cone 31is preferably somewhat steeper than customary in synchromesh devicescommonly used, this cone angle being approximately in the neighborhoodof seven degrees which will be recognized by those skilled in the art asbeing somewhat greater than the angle of rest for. the cup andcone'which 50 have in rst engaging teeth 6,6.

is ordinarily something in the neighborhood of -ve and one half degreesor less.

The ring 54 is provided with a set of synchronizing controlling externalteeth 60 adapted, prior to the synchronizing action, to lie in the pathof shifting of teeth 50 toward teeth 36 to prevent clashing of theseteeth. In order to control the operation of ring 54 from collar 5| forsynchronizing teeth 50 and 36 for conditions of rotation when teeth 36are rotating inthe same direction as teeth 56 but relatively faster orslower, the inner ends of teeth 60 are pointed or bevelled to form thefaces 6l and 62, the adjacent ends of teeth 50 being correspondinglybevelled to form the faces 63, 64 which are respectively engageable withthe faces 6I and 62. The included angle of the faces of 'teeth 6D ismade suiliciently great to` insure the synchronizing action and I havefound that an angle of approximately one hundred and ten degrees, by wayl of citing an example, will give good results.

The ends lof teeth 50 are preferably formed as illustrated in Fig. 6Bwith arcuately curved side faces tangent to planes designated at |]ahaving an included angle of approximately 90.

These planes pass through the contacts which teeth 50 have in enteringteeth 36. The teeth 36 preferably are flat sided having an includedangle of 90. y

By reason of the curved end faces of teeth 5U, the ends of the teethpresent face portions tangent to planes designated at 5|)h having anincluded angle of approximately 110. These planes pass through thecontacts which teeth Teeth 60 preferably are flat sided having anincluded angle of approximately 110.

Such arrangement` facilitates the servo-action on the ring 54 and at thesame time provides properv clutching with :teeth 36 without any deadending. y

The ends of the teeth 36 which are directed toward the teeth 50 are alsopreferably pointed at 40 to insure ready entry of teeth 50 between thespaces of teeth 36 when the synchronizing action between teeth 50 and 36has been accomplished preparatory to the final positive clutchingengagement of these teeth. A similar synchronizing control ringstructure 54a is provided between hub 42 and teeth 38 for producing asynto the driving shaft I5, the gear shift lever 28 is manipulated tooperate the shifting yoke 3| rearwardly starting from the neutralcondition of parts illustrated in Figs. 1, 2 and 4 to 6A. With thevparts in the neutral condition, the detent balls 45 are extended intothe groove 53, and the ring 54, while rotated with the hub 42, is freeto assume a position of relative rotation with respect to the hub. Forpurposes of illustration letx it be assumed that the ring 54 is also inits neutral position as indicated in Fig. 6 and by the solid lineshowing in Fig. 6A. Under such conditions, the tongues 55 are disposedmidway circhronized engagement of teeth 5|) with teeth 38 and sincethestructure of the synchronizing rings 54 and 54Ev is preferably similar,I have applied similar reference numerals to the ring 54a.

, It will also be noted that the rearwardly extending ends of teeth V38are bevelled or pointed at 4| to correspond to the pointediends 40 ofthe teeth 36.

'inasmuch as the synchronizing clutching action is substantially similarfor the opposite shifting movements of collar 5I, the description of theoperation will, for the most part, be limited to the rearward shiftingmovementof the collar for clutching the teeth thereof with the drivingteeth 36 of the second speed gear 21.

In the operation of the synchronizing mechanism let it be assumed thatitis desired to estabi `lish the second speed ratio drive for the motorvehicle and that at the time of shifting the collar 5| toward the teeth36 of gear 21, the gear 21 is rotating in the usual direction indicatedby arrows 61 and at a faster speed of rotation than that of the shaft 23along with hub 42, ring 54 and collar 5I. The operator having Aactuatedthe usual clutch to release thedrive from the engine cumferentially inthe companion recesses 41 and the teeth 60 will then be axially oppositethe spaces between teeth 50, the teeth 60 under ysuch conditionspermitting teeth 50 to pass rearwardly freely between teeth 66 but forthe synchronizing action of ring 54. It will also be observed that thereis a clearance between cup 56 and cone 31, these frictional clutchingelements being freev from-frictional engagement when the collar 5| is inthe aforesaid neutral position.

When the collar 5| is shifted rearwardly the detent balls 45 provide areleasable connection with the hub 42 so that the latter, together withring 54, is also shifted rearwardly until frictional engagement isestablished between cup 56 and cone 31. At the instant of thisfrictional engagement, the ring 54 will be rotated by the fasterrotating cone 31 in a clockwise direction a's viewed in Fig. 6. 'I'hisrotation of ring 54 will be relative to hub 42 and shaft 23 in taking upthe clearance indicated at 68 in Fig. 6 thereby moving teeth 60 relativeto teeth 50 into the dotted line position illustrated at 6|)a in Fig. 6Aso as to obstruct, for the moment, the continued rcarward shifting ofteeth 50 to engage the teeth 3 The pressure of springs 44 acting ondetent balls 45 is relatively light, it being only necessary to have thehub 42 follow the rst stage of shifting movement of collar 5| rearwardlyto 'cause the ring 54 to have the limited rotation to hub 42 as iaforesaid. At this stage of the operation, collar 5| continues itsrearward movement, the detent vballs 45 being forced inwardly so thatthe collar is then shifted axially relatively to the hub 42 as generallyindicated in Figs. 7 and 8. shifting movement of collar 5| brings-thefaces 64 of teeth 50 into enga ement with the faces 62 of teeth 60carried by he' ring 54. The rearward movement of collar 5| then urgesring 54 rearwardly to bring the cup 56 into tight frictional engagementwith the cone 31 thereby causing retardation of gear 21 and shaft |5drivingly connected therewith to synchronize the speeds of shaft 23 andgear 21. It will be understood that the gear 21, under the aforesaidassumed-conditions, will-be slowed down during the synchronizing actionrather than causing the shaft 23 to -speed up tothe rotation of gear 21inasmuch as shaft 23 is drivingly connected with the ground wheels ofthe motor vehicle andfree to respond to the rotational component exertedby teeth 50 on faces 62 for rotating the ring 54 into the neutralconditions of Figs 6 and 6A. The collar 5I is then free to continue itsrearward movement, teeth 50 freely passing between teeth 60 and intopositive engagement with the teeth 36, this last stage of the shiftingmovement of collar l being so rapid that the teeth 50 and 36 retaintheir synchronized condi tion for the final clutching action.

It should be understood that while I have described the operation of therearward shifting movement of collar 5| as comprising a series ofstages, the shifting movement of the collar in practice vis practicallycontinuous and almost instantaneousas to the impression or effect on theoperator manipulating the gear shift lever 28. When the operator desiresto move the collar 5I back to the neutral position, lit will be readilyunderstood that the teeth 50 will immediately be withdrawn forwardlyfrom the teeth 36,' the ball detents 45 again entering the groove 53 soas to restore the parts to the Fig. 1 position.

The operation in shifting the collar 5| forwardly to engage the teethwith the teeth 38 carried by the driving shaft I5 is substantiallysimilar to that previouslydescribed, the ring 54e responding to theiiitpart of the shifting movement of the collar to obstruct completeshifting movement of the collar until the rotational speeds of shaft I5and shaft 23 has been synchronized as will be readily understood.

It will be noted that my synchronizing mechanism is bi-directional inits action for synchronizing and clutching the second speed gear 21 aswell as the driving shaft I5. This is obtained primarily by providingthe pointed teeth 6I) together with the cooperating'pointed oroppositely bevelled faces at the ends of teeth 5I).v It therel fore doesnot make any difference as to the eecn with teeth 36 ofthe second speedgear 21, inthe event that the second speed gear is rotating slower thanshaft 23 and collar.5I. the synchronizing'ring 54 upon its vinitialengagement'with cone 31 will be moved in the opposite direction of thataforesaid to positionA the teeth 50 in the dotted line position 60h ofFig. 6A. Such move- `ment of `the ring relative to hub 42 is permitted nby movement of tongues 55 taking up the clearance in recesses 41indicated at 63 in Fig. 6. Such'movement places the lteeth. 60 so as toobstruct further shifting Vof teeth 5l until the faces 63 of teeth 50acted on the faces 6I of teeth 610 to synchronize the speeds of teeth 50and 316 whereupon teeth 50 will cause the ring 34 to move to its neutralposition and permit com- I pletion of the shifting movement 0f collarlilin clutching the teeth 50 with the teeth 36.- A similar operation is metin connection with shifting the collar 5I to engage the teeth 33 ofshaft I5 and in Fig. 11 I have illustrated a condition generallycorresponding to that illustrated in Fig.

.1 where the collar 5I is in the course of synchronizing shafts I5 and23 from a condition where collar 5I was rotating faster than shaftI5.priorr4 to the synchronizing operation.

The bi-directional conditions which are met with ln the type oftransmissions under consideration may be briey outlined asfollows. In

connection with clutching the collar 5I to engage teeth36 of secondspeed gear 21, such a shift is frequently made during acceleration ofthe motor vehicle in shifting from low speeds to second speeds.Under'such conditions the second speed gear 21 is ordinarily rotatingfaster than shaft 23 so that the synchronizing mechanism operates toslow down the speed of the sec- K ond lspeed lgear. 0n the other hand`where a shift is made from high or direct down to second speed, thesecond speed gear 21 `will ordinarily be rotating slower than shaft ,23so that it is necessary to speed up gear 21. In each instance thesynchronizing operation takes place between the second speed gear 21 andshaft l23, the main clutch between the engine andthe shaft I5'fbeingreleased, as aforesaid.

The bi-directional conditions for synchronizing the collar 5I with theteeth 38 of shaft I5 are ordinarily met ,with as follows. During a shiftfrom second speed to direct, shaft I5 is ordinarily rotated faster thanshaft 23 so that it is necessary to slow down shaft I5 during thesynchronizing operation. On the other hand, during the shift from-second'speed to direct where the operator may halt the shift' lever 28 inneutral until the shaft I5 slows down below the speed of shaft 23, thenit is necessary to speed up the shaft I5 in synchronizing the lspeedthereof with that of shaft 23.

The ball detents 45- betweenv collar 6I and hub' operation for thesynchronizing rings by causing the obstructing addustments of theserings by reason of the rotation of the other7 part of the mechanism tobe clutched. As soon as the ball detents 45 have been broken away, thecollar 5I forces the synchronizingring contrary to its rotating tendencyvby reasonof the servo wedge on the teeth of the synchronizing ring andthe pointed teeth 5I) carried by the collar 5 I vlis soon as thesynchronizing ring 54, for example, has rotated to its neutral positionin `'synchronizing the parts,` the servo action ceases and the ring isfree from frictional engagement with the cone 31 except for thenegligible drag of the ball detent 45 against the hub 42 only duringcompletion of the final shifting of collar 5I into en-A gagement withteeth 36. In shifting the collar 5I toward its neutral position from acondition of engagement with teeth 38' or 38, it is'of importance tonoteI that the ball detents 45 drag the hub 42 by the frictionalengagement with annular collar groove 53, to insure complete release ofcup 56 and cone 31 the instant that relative rotation at the cone takesplace. Of course,

. afterthe detent balls" 45 enter the groove 53,v the 1 previouslyreleased cup 56 is positively moved have' b therefore provide for aservo or self-energizing ,collar 5|, before ventry/bf trieben detentsinto the so that it is an advantageI to free the cup andl hub to stickon the transmission main shaft corresponding to shaft 23 in myillustration, and thereby destroy any synchronizing action inasmuch asunder such conditions the shift collar would move directly to endeavorto clutch with a set of gear teeth. With my improved arrangementhowever, even should the oil viscosity become such as to cause the hub42 to stick on with shaft 23 against sliding operation by the balldetents 45, the synchronizing cup 54, for example. will be caused torotateby the oil lviscosity at the cone 31 so that it will moverotatably to perform its obstructing action for the collar and also thesynchronizing action. Thus the synchronizing rings 54 and 54EL areseparate from hub 42 in y that they are capable of rotation relativelytheredirection, the ball detents would fail to pick up the hub withtheresult that a gear clashing would result from the opposite shiftingmovement of the collar and this, of course, would cause failure of theclutching teeth and other parts of the mechanism. With my improveddevice such conditions have been -prevented owing to my improvedrelationship of parts, including `the following in. particular.

I preferably employ an angle for the cup and cone sets which is abovethe angle of rest which is ordinarily around five and one half degreesor less. Thus I preferably use an angle o'f approximately seven degrees.A high angle could not be sed 4heretofore as a practical matter becauseit would require objectionably excessive ball detent pressure in orderto get enough bite at the frictional engagement `to obtain thesynchronizing action.

I preferably form the threads 59 on the cup 56 leaving the. cone 31 witha Aplain smooth surface. I also preferably employ threads rather thanannular serrations inasmuch as serrations would tend to roughen themating clutch surface evenly whereas the threads operate to wipe the oilfilm from the cone surface and operate on different places on the conetending to keep th cone surface smooth.

It will be noted that my bi-directional synchronizing mechanism operatesto synchronize the shaft speeds when shifting from low gear to second ordirect. Heretofore, when making such shifts, especially when maderapidly, the

ing commercial types of synchronizing devices.

4ing friction clutchingwhen the oil f'lhn' is cut and the oil isdisplaced. f

The greatest obstructing eiciency of rings 54, 54a isrequired on a downshift, from direct to second, which requires speeding up of the partsdrivingly connected to gear 21 such as the countershaft gearing anddriven parts of the usual main clutch. On an up shift, from second todi- Y.

rect, the countershaft gears have a natural tendency to slow downrequiring less obstructing eincien'cy of ring 54a.

If the second speed ring 54 had its cup 56 formed with right handthreads, instead of left hand threads as i1lustrated,'then thesynchronizing action on a shift down would tend to pull the ring 54tight on the cone 31 tending to prevent release of ring 54v at just theright tme viz., after the servo action and at the instant ofsynchronization. 'I'his is apparent because during the synchromeshaction the driven shaft 23 and cup 56 are driving cone 31 on secondspeed gear 21, the main clutch being disengaged, and this drive wouldproduce the aforesaid objectionable action at cup 56 and cone 31 ifright hand threads were used at cup 56. During all synchromesh actionsit must be borne in mind that the car, through shaft 23, is the driver.However, the provision of left hand threads 59 on cup 56 opposes thisobjectionable tendency since the cup tends to thread away from the cone,thereby facilitating the desired synchronizing action.-

The rings 54 and 54B are preferably identical so that they areinterchangeable. This is a decided production and assembly advantage andavoids any tendency to getting the rings mixed as might result if ring54a had right hand threads' and ring 54 left hand threads.

The action of synchromesh at ring 54' isV to slow down the main drivepinion I6, and` parts connected thereto, so that'ring 54' becomes aretarding device and the left hand threads on ring 54al tend to .threadthe ring off the cone 39.

If the car is stopped and a shift to direct is made,

The threads 59, instead of being brought to i -extent of losing thenecessary` predetermined clearance between the friction clutchingmembers 31, 56 for example. It will be observed that the thread spaces1l provide for oil retreat durthe ring 54e is still a retarding deviceresulting in the same unthreading action of the ringbecausel of theinertia of the parts connected to shaft I5 often augmented by rotativedrag through the main clutch when disengaged.

In the shift up, from low 'to second, the gear 21 going faster than ring54, this ring vthreads on the cup 31 immediately on engagement. Sincethe synchromesh action is practically instantaneous the threadingtendency disappears since the servo action is dissipated. This is anadvantage because the threading-on action increases the 'rapidity of thesynchromesh. action.

All up,.shifts, to faster driving speed ratios, give rise to retardingeffects at the synchronizers and all down shifts, to slower drivingspeed ,ra-

tios, give rise to accelerating effects at the syn- I chronizers withvrespect to correspondingslowing down or accelerating the countershaftgearing and driven parts of the main clutch. Whenever the gear to whicha synchromesh'shift is made is to be retarded then a threading-on actionis desired and whenever such gear is to be accelerated a threading-offvaction is desired at ring 54 or 54B. The' provision of left hand threadsfor both rings 54 and 54a best meets these re-y left hand threads, thereis so little differential shift that a screwing-on effect of the ring isnot so necessary. In this connection the inertia of the countershaftgearing and driven parts of the main clutch plays an important partsince a mechanical advantage arises at the main drive pinian I6 byreason of its mesh with a larger gear I1 making the threading-on action'at the direct control ring 54 less important than at the second vspeedcontrol ring 54 because'the second speed gear 21 is driven at areduction and by torque multiplication from the countershaft gearing.Thus, in a vshift from low to second the threading-on action of ring 54provides a high degree of servo action, and on a shift down from thirdto second the ring 54 has a desired threading-off action at thisfunction of requirement for greatest obstructing eiiciency as aforesaid.

I therefore deem itadvisable, everything considered, to employ left handthreads 59 at both rings 54 and 54, the second speed synchronizer ibeing the more important so that if desiredv the ring 54 might' beformed with right hand threads. By left hand threads I mean a thread ofopposite hand to the handof rotation of the member engaged by thethread. It is of course standard practice to rotate the drive shaft I5in a right hand direction of rotation and this likewise causes righthand rotation of the gears I6, 21 as well as driven shaft 23 for directand second speed drives. ThusI the left hand threads cause the controlring 54, forexample, in the worst condition of a down shift fromsdirectto second, to strip off or to be forced away from the @friction cone 31at theinstant of synchromesh thereby preventing dead ending of sleeveteeth 50 at the teeth 36 of the second speed gear 21 because the controlring teeth 60 then no longer are coni nected to gear 21 and 'thereforedo not guide the sleeveteeth which are free, to adjust themselvesrelative to the gear teeth 36.-

Referring to the modification in Figs. 13 and to be employed in lieu ofthe Fig. 2 synchronizer.

In Fig. 13, the axially shiftable hub 42B functions as in Fig. 2 withcollar 5 I and control rings 12, 12 which have functions similar tocontrol rings 54, 54. However, the identical rings 12, 12' each has itsclutching cu'pl formed integrally with the ring and threaded at 59A asin Fig. 12. Each ring -in Fig. 13 has a series of axially extendingtongue parts 55 projecting as in Fig. 2 but each tongue 55 has its sidesrounded at 13 (see Fig. 14) to fit the walls of one'of/a plurality ofdrilled recesses or apertures 41B- each of which has its axis parallelto that of shaft `23. The

hub 42a as with Fig. 3).

The operation of the Fig. 13 structure is identical with that describedin detail in connection with Fig. 2, as will be readily apparent, sothat such operation willy notbe repeated.

Referring to the embodiment illustrated in .Fig..15, and the companionshowing in Fig. 16,

I have illustrated a synchronizer to replace that shown in Fig. 2 orFig. 13.

In Fig.`15 the hub 42b is axially fixed on splines 33 by 'ring 32a and aforward snap ring 14, this hub being shown with drilled apertures 41afor vtongue projections 55'of control rings 12, 12

as in Fig. 13. 'I'he hub 42b has a second series of axially drilledholes 15 each receiving a com- *pression coil spring 16 which has itsends acting on the rings 12, 12 respectively. Springs 16 may be termedspreader springs in that they yieldingly urge rings 12, 12a apart andinto frictional contact with' cones 31, 391v1 respectively. In Fig. 15it is no longer necessary to employ the ball detents of Fig. 2 since hub42b is axiallyvxedx and since I have provided other means forestablishing the rotative positioning of rings 12, 12a in taking upclearance 68 or 69 to obstruct the positive clutching between the teeth'50b of shift sleeve 5 Ib and teeth 36 or 38 prior to the synchronizingaction.

The teeth 50b of sleeve 5|b as well as teeth 49h of hub 42b are nowuninterrupted owing to the arrangement 'of drilled apertures 41a andtheabsence of groove 53 of Fig. 2.

The means at springs 16 impart a light rotative drag on gears I6 and 21,relative to shaft 23, thereby providing brakingl means for the drivenparts of the main clutch as well as the countershaft clusterv gear setso that the synchronizlng action is facilitated for all speed ratiochanges of the transmission including low and reverse. This is veryimportant when shifting into low and reverse from th'e usual conditionof apertures 41a are preferred in quantity produc- Y tion to the Vmilledapertures 41 of Fig. 2 since apertures 41 may be formed in a singlemultiplei drilling operation through the hub 42 instead of anddirectspeed shifts.

vseparate milling operations for the aperturest41 i the vehicle standingstill. At such times shaft 23 is non-rotating and as soon as the mainclutch is released preparatory to a shift from neutral to reverse, thesprings 16 acting to engage rings 12, 12a with cones 31,'39 respectivelywill brake the rotation of the parts .drivingly connected to gears I6andA I1 and thereby prevent tendency of these parts to spin" afterdisengagement of yth'e main clutch. This braking action, by holding thecountershaft set from spinning allows shift of gear 26 into gear I9 orgear 22 without objectionable noise or damage to the g .ar teeth.

I have therefore provided simple means for utilizing the synchromeshmeans for th'e second and direct speeds to also synchronize the gearsfor the low and reverse speeds', this means also simplifying thesynchromesh means and facilitating its operations in connectionjwithsecond By xing hub 42b axially, oil shear at splines 33 is eliminatedthereby facilitating the operation of the device especially under winterconditions. When a shift is made to establish direct, for example,sleeve 5I'J is thrust forwardly but does not move control ring 12a toestablish the servo action at cone 39 since springs 16 maintain ring 12ain light frictional engagement with cone 39 so as to misalign teeth 5I!band th'e teeth 60 of yring 12a. When sleeve 5Ib is shifted forwardly tothrust against teeth 60 of ring 12B then the the Yteeth as f hub 42 (seeY `the uninterrupted 4internal teeth points between tongues 55d.

ring 12a is thrust Ainto increasingfrictional engagement with cone 39 tosynchronize gear I6 with shaft 23 and, as in the Fig. 2 structure, thesleeve 5|b then moves into positive clutching with teeth 38. Thereforethe synchronizing action for gears I6 or 21 in the Fig. 15 structure issubstantially the same as in the Fig. 2 structure with the exception ofthe establishment of the rotation of either ring 12 or 12 relative tohub 42b to mis-align the teeth on the ring with those on the hub andshift sleeve.

Fig. 17 is similar to the Fig. 15 arrangement with the exception that inFig. 17 the hub 42': is now free to axially slide on splines 33, and theball detents 45 of Fig. 13 are incorporated to form the releasableconnection between sleeve 5I and hub 42C. If desired this arrangementmay be used to advantage, the spreader springs 16 functioning as in Fig.15 but in Fig. 1'1 shifting the sleeve 5|c carries hub 42c during thefirst part of sleeve shift as in Fig. 2. Where one or more spreadersprings are used to act on both ofA the control rings, I prefer to x,the hub aginst axial shift as in Fig. because under such conditions itis not necessary to shift the hub to establish obstructing rotation ofthe control rings during synchromesh shift.

In Figs. 18 to 21, I have illustrated a further synchromesh arrangementwhich may be used in place of any of the aforesaid synchromeshorganizations. In Fig. 18 the hub 42d may be axially slidable or fixedas illustrated by stops 14 and 32l at splines 33. This hub is formedwith peripheral teeth 49d engaged, as before, with 50G1 sleeve. 'I'heteeth'49d are interrupted by the annular channeled groove 11 formed inhub 42d, the groove 11 opening outwardly and receiving an expansion ring18 which is split at 19 for convenient installation. Ring 18 iscompressed and yieldingly expands to frictionally engage sleeve teeth50d.

Hub 42d has a series of outwardlyopen axially extending recesses orapertures 41d which may be conveniently formed by milling across the hubat the time of cutting the teeth. Extending into these apertures are thetongue projections 55dl of control rings 80, 88EL which are otherwiseidentical with rings 54, 54a of Fig. 2. Projections55d, as in Fig. 2,have clearances 68, 69 with the apertures for the same purpose as thataforesaid.

The expansion ring 18 engages the inner ends of projections 55d. Controlring 88, 80 preferably have clearance at 8l with teeth 5|)d andclearance at 82 is provided between the inner Wall of apertures41d andtongues 55d so that the control rings iloat. Thus the control rings 88,8l)a are self-centering at the engagement of threads 59 with cones 31,39 .respectively and the threads 59 may more readily release thefrictional engagement during vthreading-out functions as set forth forthe Fig. 2 structure.

Instead of using a spreader spring of coil spring type as in'Fig. l5, Ihave illustrated in Fig. 18 (see also Fig. `21) a spreader spring 83 inthe form of at spring steel or bronze for anti-rust, this spring havingintegral tongues 84 formed vby cutting the body portion 85 at 85 andbending the tongues so that they will exert axial thrust when installed.The at body portion 85 rests against the forward face of hub 42d andtongues 84v thrust against the face 81 of ring 80*l at The spring 83 hasthe body portion 85 thereof formed with a series of shiftv `xecl againstaxial sliding onshaft 23 in this embodiment. The control ringA 80 isillustrated free from frictional engagement with cone 31.

When the direct teeth 38 are to be clutched by teeth d of shift sleeve5|d, the latter is moved forwardly but does not have to establishobstructing rotation of control ring 81)*l since spring- 83 performsthis function. Sleeve 5|d is forced toward teeth of ring 80a tosynchronize gear I8 with shaft 23 to permit completion of forward shiftof sleeve 51d just as in the Fig. 2 structure. On the Areturn shift thethreads or teeth 59 of ring 802L float the ring as aforesaid. Shift ofsleeve 5ld forwardly relative to rings 80, 80' is permitted by slippingat thefriction expansion ring 18.

When second speed is to .be obtained, sleeve 5|d is shifted rearwardly.The initial shift of the sleeve carries ring 80 rearwardly with thesleeve by reason of the friction connection afforded bythe expansionring 18. As soon as the threads 59 of control ring 80 engage cone 31 thecontrol ring is rotated to obstruct further and final shift of thesleeve until the sleeve thrust acting on the control ring synchronizesgear 21 with shaft 23. When sleeve teeth 50d then shift across the teeth60 of control ring 80 toclutch with teeth 36 of gear 21, releasing thering 80 `for floating at its threads 59, the sleeve 51d slips across theexpansion ring 18 which cannot move axially any further than the controlring. Return shift of the sleeve moves ring 8l)a forwardly by thefriction at ring 18, the threads 59 thereby cutting through the oeil lmat surface 39 to prepare these friction surfaces for synchronizingaction even before sleeve 5Il reaches the Fig. 18 neutralposition duringsaid return shift.

A ring 18 of rectangular cross section isnpreferred since it providesrelatively great frictional contact efficiency. The spreader spring 83functions to exert frictional drag on gear I6 so as to facilitate allspeed. ratio changes of the transmission as in the case of the coilsprings 16 a1- though the latter in Figs. l5 and 17 are arranged toexert the drag at both gears I6 and 21.

The expansion ring 18, in providing a frictional releasable connectionbetween sleeve 5ld and hub 42d, affords improved ease of operation andpresents an arrangement much simpler and less' l costly than the baudetents as of Fig. 2.

If desired both of the control rings may be initially-moved intofrictional engagement for the limited rotation relative to the hub inestablishing the obstructing action for the shift sleeve as shown inFig. 22. In this embodiment, the spreader spring of Fig. 18-isomittedand the expansion ring 18a is shown of circular cross-section whichaffords somewhat less friction surface engagement than 'ring 18 butprovides greater unit pressure because of the lesser surface of contact.The parts are otherwise as shown in Fig.

18 and their functions are the same.

In Fig. 22 forward shift of sleeve 5Il first moves control ring a withthe sleeve to engage cone 39 thereby rotating control ring 80a into its0bstructing position, the expansion ring 'I8a affording the connectionbetween the sleeve and the control ring. Continued forward s'hift of thesleeve synchronizes teeth 38 with teeth vBild as before to accommodatecompletionof the forward shifting of the sleeve, the sleeve slidingbeyond the expansion ring 18. 'I'he synchronization isfpracticallyinstantaneous so that control ring 80 is free from thrustaxally duringthe secondary phase of shifting ofthe sleeve across teeth 60.

The rearward shift of sleeve Bld to clutch tee h 38 vacts through theexpansion ring 18 to in tially move control ringBO in the same manner asineffecting the direct speed clutching. In

both Figs. 18 and 22 the hub annular 4groove 11 is of such width axiallyto accommodate axial movement of the control ring 18 or 18 to establishthe initial clutching with the respective friction cones and for thefurther slight axial. movelnient of the control rings in effectingsynchronization of the parts.

I do not limit my invention, in the broader aspectsA thereof, to anyparticular combination K and arrangement of partssuch as shown anddescribedfor illustrative purposes since various modifications will beapparent from the teachings of my invention-and'scope thereof as denedin the appended claims.

What I claim is:

,'1. InI a synchronizing clutch mechanism for automotive change speedtransmissions, relatively rotatable shafts to be clutched. positivelyen'- gageable clutch elements respectively driven with said shafts, afriction cup clutching member driven with one of said'shafts, a frictioncone clutchawo 3. In @synchronizing clutch mechanism for automotivechange speed mechanisms, a rotatable driving member, a driven shaftcoaxial with the laxis of rotation of said driving member, drivingclutch teeth rotatable with said driving member, a driving frictionclutch part rotatablewith said driving member, a hub structure mountedon said shaft for rotation ltherewith, a shiftable sleeve splined tosaid hub structure and having clutch teeth adapted to clutch with saiddriving clutch teeth, a synchronizing structure driven with saidv hubstructure and having predetermined rotation tion surface threaded, thethreads being of such' a hand with relation to the hand of rotation ofthe friction clutch part engaged by said threads as to force thethreaded friction clutch part away from the other friction clutch partat approximately the instant of synchromesh thereby faeintatingclutching of said sleeve teeth with said driving teeth.

ing member driven with the other of said shafts,

means for forcing one of said friction clutching .members against theotherto synchronize -said shafts -and for subsequently shifting one ofsaid positive clutch velements into' engagement with the other, one ofsaid friction clutching members having its friction surface threaded,saidl threads being of suitable pitch and in number in excess ofapproximately thirty per inch to present a relatively small frictionsurface area capahleof` substantially instantaneously cutting throughthe oil film between the friction surfaces of said members and therebyprovide relatively high unit pressure of engagement of said: frictionmembers affording substantiallyinstantaneous synchronization of saidshafts and minimization of wear of the engaging friction surfacesof-said friction clutching members.

2.l In a synchronizing clutch mechanism for automotive change ,speedtransmissions, rela-iy tively rotatable shafts to beclutched,positively` engageable clutch elements respectively driven withsaid shafts, a. friction cup clutching member driven with'one of'saidshafts, a friction cone A' clutching member driven with the other ofsaid shafts, means for. forcing one, of said friction clutching membersagainst the other to synchronize said .shafts and for.' subsequentlyshifting one of said positive clutch-elements into engagei having afriction clutch Vpart adapted for fric- K 4.,In a synchronizing clutchmechanism for automotive change speed transmissions, coaxially aligneddriving and driven shafts, a primary drivinggear driven with the drivingshaft, clutch teeth driven with the primary gear, a friction clutchmember driven with the primary gear, a secondary driving gear loose onthe driven shaft and driven from the primary gear in the same directionbut at a different speed, said driving direction being right handed whenviewed from the driving shaft toward the driven shaft, clutch teethdriven with the secondary gear, a friction clutch member driven with thesecondary gear, a` hub structure drivingly connected to said drivenshaft and disposed intermediate said gears, :said hub structure havingperipheral splines, a pair of interchangeable similar synchironlzingcontrol rings respectively disposed between said hub structure and oneof said gears, each of said rings carrying peripheral teeth and tionalengagement with one of said clutch members, means drivingly connectingsaid control rings-with said hub structure for limited rotation relativethereto, and a shift sleeve having clutchteeth engaging the splines ofsaid hub structure and adapted for shifting movement ment with theother, one lof said friction clutching .members having its frictionsurface threaded.'v

said threads being of relatively low pitch, in excess ofapproximatelythirty per inch, toy present a relatively small frictionsurface area capable of substantially instantaneously cutting throughthe oil lm between the friction surfaces of said members and therebyprovide relatively high unit pressure of engagement of said frictionmembers affordingv substantially instantaneous synchronization ofisaidshafts and minimization of wear of the engaging friction surfaces ofsaid frictionv clutching members.

selectively in opposite directions between the teeth of said rings andtherebeyond for clutching with the clutch teeth of said primary andsecondary gears, the teeth carried by said rings being adapted toselectively` obstruct shifting movement of said sleeve teeth prior tosynchronization of the driven shaft with one of said gears, each of saidrings having its friction clutch part threaded, the threads being of aleft hand..

5. In a synchronizing lclutch mechanism for automotive change speedtransmissions, a pair of coaxial relatively rotatable driving and drivenmembers to be clutched, said driving member having driving clutch teethand a friction clutch part rotatable therewith, ahub structure formedvwith peripheral splines, means for. mounting said hub structure on saiddriven member for rotation therewith, a shift sleeve ha g driven clutchteeth engaging said splines an shiftable with said sleeve to clutch withsaid driving clutch teeth, a synchronizingv structure having a frictionclutch part engageable with said drivingmember-clutch-part, meansdrivingly connecting said synchronizing structure with said hubstructure and accommodating predetermined rotation relative thereto formovement of said synchronizing structure from a first position ofobstructing shift of said sleeve to a second position permitting shiftof said sleeve, yielding means acting on said synchronizing structure toengage the clutch part thereof under relatively light pressure with saiddriving-member-clutch-part prior to shift of said sleeve toward saiddriving clutch teeth whereby said synchronizing structure is disposed toselectively clutch with said sets of clutch teeth,

with said hub and having clutch teeth adapted v ture, each of saidcontrol structures having a in its said obstructing position, and meansre- Y m'ent of said synchronizing structure to its said secondposition.

V6. In a synchronizing clutch mechanism for automotive change speedtransmissions, a pair of coaxial relatively rotatable driving .anddriven members to. be clutched, said driving member having drivingclutch teeth and a friction 'clutch part rotatable therewith, a hubstructure formed with peripheral splines. means for mounting said tiontherewith but preventing movement of said hub structure axially of saiddriven member, a

shift sleeve having driven clutch teeth engagfriction clutch partengageable with one of said friction clutch elements and a stop forcontroli member's together for rotation at different speeds,

,Y a driven member adapted to selectively receive a drive'from saiddriving members, a hub structure. means mounting said hub structure onsaid driven member for rotation therewith but preventing` movement ofsaid hub structure axially Ihub structure on said driven member forrotaing said splines and shiftable with said sleeve rel-` I ative tosaid hub structure to clutch with said driving clutch teeth, asynchronizing structure having a friction clutch part engageable withsaid driving-member-clutch-part, means drivingly connecting saidsynchronizing structure with said hub structure accommodating axialmovement of said synchronizing structure and predetermined rotationthereof relative to said hub, structure for movement of'saidsynchronizing structure from a first position of obstructing of saiddriven member," a shift device driven with .said hub structure andhaving clutch teeth adapted to selectively clutch with said sets ofclutch y teeth, a'synchronizing control structure disposed between eachof said driving members and said hub structure, each of said controlstructures having a friction clutch part engageable with one of -saidfriction clutch elements and a stop for controlling shift of said shiftdevice, said hub structure having an annular peripheral groove y and aplurality of axially extending apertures inshift of said sleeve to asecond position permittin shift of said sleeve, yielding means acting onsai synchronizing structure to move the same axially to engage theclutch part thereof under relatively light pressure with saiddriving-member-clutchpart prior to shift of said sleeve toward saiddriving clutch sleeve whereby said synchronizing.`

structure is disposed in its said obstructing position, and meansresponsive to shift of said sleeve toward said driving clutch teeth forvurging said clutch parts relatively together under relatively heavypressure to synchronize said members and thereby effect movement of saidsynchronizing structure to its said second position.

'7. In a synchronizing clutch mechanism according to claim 5, whereinthe yielding means comprises a ring member having a body portion and ayielding tongue portion deflected therefrom, one of said portionsengaging the hub structure and the other of said portions engaging thesynchronizing structure.

8. In a synchronizing mechanism for motor vehicle transmissions;coaxial'driving members each carrying a set of clutch teeth and afriction clutch element, means drivingly connecting said memberstogether for rotation at different speeds. a driven member adapted toselectively receive tersecting said annular groove, each of said controlstructures having tongues respectively extending in said apertures withclearance accommodating limited rotation of said control structuresrelative to said hub structure, an expansion ring disposed in saidannular groove in frictional expanding engagement with said shiftdevice; said annular groove accommodating axial shift of said expansionring therein, the tongues of said control structures being Aengageableby said expansionri'ng whereby said expansion ring provides a releasableconnection between said shift device and said control structures toeffect selective engagement of said friction clutch parts respectivelywith said friction clutch elements, said expansion ring accommodatingadditional shift of said shift device relative to said control devicesfor effecting selective clutching of the clutch teeth of the shiftdevice with said sets of clutch teeth.

v l0. In a synchronizing clutch mechanism for automotive change speedtransmissions, coaxially aligned driving and driven shafts, a primarydriving gear driven with the driving shaft, clutch teeth driven with theprimary gear, a friction clutch member driven with the primary gear, asecondary driving gear loose on the driven shaft and driven from theprimary gear in the same member driven withfthe secondary gear, a hub adrive from said driving members, a hub strucstructure drivingiyconnected to said driven shaft and disposed intermediate said gears.said hub structure having peripheral'splines, a pair of interchangeablesynchronizing control rings respectively disposed between said hubstructure ate said driving members, a shift device driven peripheralteeth and having a friction clutch part adapted for frictionalengagement with one of said clutch members, means drivingly connectingsaid control rings with said hub structure forlimited rotation relativethereto, and a shift sleeve having clutch teeth engaging the splines ofsaid hub .structure and adapted for shifting movement selectively inopposite directions between the teeth of said rings and therebeyond ,forclutching with the clutchteeth of said primaryand secondary gears, theteeth carried by said rings being adapted to selectively obstructshifting movement of said sleeve teeth prior to synchronization of thedriven shaft with one of said gears, each of said rings having itsfriction clutch part threaded, said rings having clearance with saidshift sleeve and said hub structure in a direction transversely to theaxis of rotation of said shafts whereby to accommodate support of saidrings at the threads thereof on said clutch members respectively.

l1. In a synchronizing clutch mechanism for automotive change speedtransmissions, driving means comprising two rotating structures eachincluding a friction clutch member and a set of clutch teeth, a drivenshaft adapted to be selectively clutched 'with said structures, a hubcarried by said shaft and having an annular body portion and aperipheral splined rim overhanging said body portion in a directionaxially of said shaft, said rim having a portion thereof cut away toform an aperture in said body portion and a pair of oppositely extendingopenings respectively at the junctures of said rim and body portion,

a synchronizing control ring disposed between said hub and each ,of saidstructures, each of said rings having an axially-extending tongueprojection with rotative clearance through one of said l ltions undercontrolA of said ring stops for effecting synchronized engagement withsaid sets of clutch teeth.

12. In a synchronizing clutch mechanism for' automotive' change speedtransmissions, driving means comprising a rotating structure having a.friction clutch member and a set of clutch teeth,

a driven shaft adapted to be clutched with said structure,a hub carriedby said shaft and having an annular body portion and a peripheralsplined rim overhanging said body portion in a direction axially of saidshaft, said rim having a portion thereof cut away to form an aperture insaid body portion and an opening at the juncture of said rim and bodyportion, a synchronizing control ring disposed between said hub and saidstructure and having an axially extending tongue projecting withrotative clearance through said opening to rotatably connect said huband ring while accommodating limited rotation of said ring relativeto'said hub, said tongue having an end portion thereof disposed in saidaperture, said ring having a friction clutch part engageable with sai-dfriction clutch member and a stop, and

a shift sleeve having clutch teeth engaging the splines of said rim andadapted for shifting movement under control of said stop for effectingsyna body portion carried bysaid shaft, said hub\ having its peripheryformed with splines extending in a direction axially of said shaft, saidhub having a slot extending inwardly through a portion of said splinesto provide a tongue-receiving recess opening axially in oppositedirections from said body portion, a pair of synchronizing control ringsrespectively disposed between said hub and each of saidstructures, eachof said rings having `an axially extending tongue projecting withrotative clearance through one of said recess openings to rotatablyconnect said hub and rings while accommodating limited rotation of saidrings relative to each other and relative to said hub, the tongueshaving end portions disposed .in said recess adjacent each other, eachof said rings having a friction clutch part engageable with one of saidfriction clutch members and a stop, and a shift sleeve having clutchteeth engaging the splines of said hub and adapted for shifting movementselectively in opposite directions under control of said ring stops foreffectling synchronized engagement of the clutch teeth of said shiftsleeve with said sets of clutch teeth.

14. In ay synchronizing clutch mechanism for automotive change speedtransmissions, driving means comprising a rotating structure having afriction clutch member and,a set of clutch teeth, a driven shaft`adapted to be clutched with said structure, a hub having a body portioncarried by said shaft, said hub having its periphery formed with splinesextending in a direction axially of said shaft, said hub having alslotextending inwardly throughl a portion of said splines to provide atongue-receiving recess which opens axially from said body portion, asynchronizing control ring disposed between said hub and said structureand having an axially extending tongue projecting with rotativeclearance through said recess opening to rotatably connect said hub andring while accommodating limited rotation of said ring relativel tosaid'hub, said tongue having an end portion thereof disposed in saidrecess, said ring having a friction clutch part engageable with saidfriction clutch member and a stop extending transversely of said tongue,and a shift sleeve having clutch teeth engaging the splines of said hubandv adapted for shifting movement under control of said stop foreffecting synchronized engagement of the clutch teeth of said shiftsleeve with said set of clutch teeth.

15. In a synchronizing clutch mechanism for automotive change speedtransmissions, driving means comprising two rotating structures eachincluding a friction clutch member and a set of clutch teeth, a drivenshaft adapted to be selectively clutched with said structures, a hubhaving a body -portion carried by said shaft, said hub having itsperiphery formed with splines extending in a direction axially of saidshaft, the body rings respectively disposed between said hub and each ofsaid structures, each of said rings having an axially extending tongueprojecting with rotative clearance through one of said recess openingsto rotatably connect said hub and rings while acv commodating limitedrotation of said rings relative toeach' other and relative to said hub,the `tongues having end portions disposed in said recess adjacent eachother, each of said rings having a friction clutch part engageable withone i of said friction'clutch members and a stop, and

a shift sleeve having clutch teeth engaging the splines of said rim andadapted for shifting movement selectively in opposite directions undercontrol of said ring stops for effecting synchronized engagement of theclutch teeth of said shift sleeve with said sets ofy clutch teeth.

16. In a synchronizing clutch mechanism for automotive change speedtransmissions, driving means comprising twcrrotating structures eachincluding a friction clutch member and a set of hub and rings whileaccommodating limitedrotation of saidrings relative to each other andrelative to' said hub, the tongues having end portions disposed in saidaperture adjacent each other, each of said rings having a frictionclutch part engageable with one of said friction clutch members and astop, and a shift sleeve having clutch teeth engaging the splines ofsaid rim and adapted for shifting movement selectively inv oppositedirectionslunder control of said ring vstops for effecting synchronizedengagement of the clutch teeth of said shift sleeve with said sets ofclutch teeth.

17. In a synchronizing clutch mechanism for automotive change speedtransmissions, relatively rotatable shafts to be clutched, positivelyengageable clutch elements respectively driven with said shafts, afriction cup clutching member driven with one of said shafts, a frictioncone clutching member driven with the other of said shafts, means forforcing one of said friction clutching members against the other tosynchronize said shafts and for subsequently shifting one of saidpositive clutch elements into engagement with the other, said'frictionclutching members having relatively engageable frictionaliy activeportions one of which comprises a substantially continuous threadpresenting a spiral friction surface whose area is materially less thanhalf of the friction surface area of the other of said frictionallyactive portions capable of substantially instantaneously cutting throughthe oil film between said frictionally active. portions and therebyproviding relatively high unit pressure of engagement of saidfrictionally active portions affording substantially instantaneoussynchronization of said'shafts and mininization of wear of the engagingfriction surfaces, vsaid thread being of such a hand with relation tothe hand of rotation'of the frictionally active portion engaged therebyas to cause the threaded friction clutching member to be forced awayWfrom the other friction clutching member at approximately the instant ofsynchromesh thereby facilitating clutching of said positive clutchelements.

18. In a synchronizing mechanism. two relatively rotatable parts eachhaving a set of clutch v teeth and a friction clutching member, a thirdpart adapted for selective drive relation with the rst two said parts,ya hub structure carried by Said third part intermediate the first twosaid parts; a shift device having drive connection with said'hub andhaving clutch teeth adapted for selective clutching with said sets ofclutch teeth,

' engagement with said friction clutching members respectively.

19. vIn a power transmitting mechanism including rotatable 'driving anddriven structures adapted to Ibe positively clutched, one of saidstructures carrying a set of clutch teeth and a y frusto-conicalfriction surface, the other of said g 25i structures being fixed againstmovement axially thereof and having teeth formed externally thereon, aclutch sleeve `encircling said l other structure and having teethlformed internally thereon for engagementwith said external teeth suchthat said clutching sleeve is shiftable axially relative to said otherstructure to clutch said internal teeth with said set of clutch teeth,the teeth of said sleeve being axially spaced from said set oi clutchteeth prior to clutching shift of said sleeve, a blocker having afrust-conical portion thereof adapted to engage said friction surfaceunder relatively light blocker-energizing pressure and having blockerteeth projecting into said space prior to clutching shift of saidsleeve, said blocker having a connection with said other structurecompelling rotation 'therewith but accommodating limited rotation of theblocker relative to said other structure for accommodating positioningoi.' said blocker teeth in blocking relationship with respect to theteeth of said clutching sleeve when said structures are rotating atrelatively different speeds and for disposing said blocker teeth out ofsaid blocking relationship thereby to accommodate shift of saidclutching sleeve as aforesaid when said structures are rotating atapproximately the same speed, and a spring yieldingly acting to urgesaid blocker portion into constant engagement with said frictionlsurface for maintaining said blocker in said blocker-energizingengagement with said friction surface whereby to induce said positioningof said blocker in said blocking relationship prior to clutching shiftof said clutching sleeve.

20. In a synchronizing mechanism, two relatively rotatable parts eachhaving a set of clutch teeth and a friction clutching member, a thirdipart adapted for selective drive relation with the first two said parts,a hub structure .carried by said third part intermediate the first twosaid parts, means for securing said hub structure to said third part soas to prevent their relative displacement in the direction of -theiraxis of rotation, a shift device having drive connection with .said huband having clutch teeth adapted for selectivey clutching with said setsVof clutch teeth, friction clutching surfaces drivenwith said hub andadapted for displacement relative to each other for respectivelyclutching with said friction clutching members in response to selectiveshift of said shift device, land means operatively disshifting movement,

posed between said shift device and said friction clutching surfaces andincluding a split ring-like f expanding element, the last said meansbeing'so constructed and arranged as to selectively transmit thrust fromsaid shift device to said friction clutching surfaces thereby to engagethe latterl respectively with said friction clutching members.

2l. In a power transmitting mechanism ac- I .cording to lclaim 19,wherein, said blocker portion comprises a helically threaded surface.

2,2. In a synchronizing transmission, a driving member having a frictionclutch face and a jaw clutch element, a driven shaft coaxial with saiddriving element, a hub thereon. a movable clutch elementencircling andmounted upon said hub in driving engagement therewith and axiallymovable with respect thereto, for" engagement with said Jaw clutchelement on the driving member, a blocker synchronizer ring having afric-tion clutch face for engagement with the .resilient meansinterposed between said hub and said synchronizer ring, adapted tolightly maintain said synchronizer ring in frictional engagement withthe friction face of said driving member, whereby to normally maintainsaid synchronizer ring biased in blocking relation to said movableclutch element, so that engagement of the latter with said blockingmeans during the initial stage of shifting movement, serves to transmitaxial thrust from the movable' clutch element tothe synchronizer ringfor effecting synchronizing engagement between said friction clutchfaces. i

23. In a synchronizing transmission, a pair of alignedtorque-transmitting shafts, an axially fixed hub secured to one of saidshafts, said hub having an axially extending annular depression forminga rim, a jaw clutchelement encircling said rim, drivingly connectedthereto, and axially movable thereon, a jaw clutch element drivinglyassociated with the other shaft and adapted to be engaged by saidmovable Jaw clutch element when the latter isfshifted axially, thus toestablish a positive drive connection between said shafts, a frictionclutch element drivingly associated with said other shaft, asynchronizer ring received in the annular depression in the hub, saidring having a friction clutch face for coaction with said frictionclutch element, having a lost motion driving connection with the hub,and including blocking means adapted, in one of its positions permittedby said lost motion connection, to block the path of axial shiftingmovement o f said movable clutch element, and, in another of such positions, to allow the movable clutch element to complete its axialshifting movement, and means for causing said synchronizer element tocontinuously receive a slight amount of torque from said other shaft soas to normally maintain said synchronizer element biased in blockingrelation to said movable clutch element, whereby engagement of thelatter with said blocking means during the initial stage of serves totransmit axial thrust from the movable clutch element to the having anaxially extending annular depressicn forming a ri'm, a'jaw clutchelement encircling said rim, drivingly connected thereto, and axiallymovable thereon, a jaw clutch element drivingly associated with theother shaft and adapted to .be engaged by said movable jaw clutchelement when the latter is shifted axially, thus to estab` lish apositive drive connection between said shafts,- a friction clutch.element drivingly associated with said other shaft, a synchronizer ringreceived inthe annular depression in the hub, said ring having afriction clutch face for coaction with said friction clutch element,having a lost motion driving connection with the hub, and includingblocking means adapted, in one .of its positions permitted by said lostmotion connection, to block the path of axial shifting movement of saidmovable clutch element, and, in another of such positions, to allow themovable clutch element to complete its axial shifting movement, andmeans for maintaining said synchronizer element in constant lightfrlctional engagement with said other friction clutch element so as tonormally maintain said synchronizer element biased in blockingrelationto said movable clutch element, whereby engagement. of `thelatter with said blocking Ameans during the initial stage of shiftingmovement serves lto transmit' axial thrust from the movable clutchelement to the synchronizer element for effecting synchronization.

25. In a synchronizing transmission, a pair of torque-transmittingmembers mounted in axial alignment, a hub carried by one of saidmembers, means for iixing'said hub against movement axially of said onemember, a movable jaw clutch element carried by said hub and adapted tobe moved axially into engagement with a jaw clutch element carried byV,the other member thus to establish a positive drive connection betweensaid members, a, synchronizer element driven by said one member andadapted to be moved axially into frictional driving engagement with afriction clutch element carried by said other member so as to effectsynchronization of said members, and

an annular thrust member of spring material arranged coaxially with saidtorque-transmitting members, having an axial thrust-transmittingconnection with said synchronizer element and being biased undercompression in radially voutwardly directed yielding engagement with theinterior -of said movable clutch element, whereby to transmit axialmovement from said movable clutch element to said synchronizer element.

26. In a synchronizing mechanism, two relatively rotatable parts to beclutched onehaving a set of clutch teeth and a friction clutching memberrotating therewith and the other having a friction clutching elementrotating therewith and adapted for displacement to engage the frictionclutching member, the last said part having Iexternal splines, a hollowAshift sleeve having at least a portion of its interior si'rface splinedfor sliding tfwith said external splines, and a radially expanding ringfrictionally engaging said shift sleeve for shift therewith to effectsaid displacement of said friction clutching element and accommodatefurther shift of said shift sleeve to clutch teeth.

27. In a synchronizing clutch mechanism for the utter with said set ofCiutch automotive change speed transmissions, relatively rotatableshafts to be clutched, positively engageable clutch elementsrespectively driven with said shafts, afriction cup clutching memberdriven with one of said shafts, a friction cone clutching member drivenwith the other of said shafts, means for forcing one of said frictionclutching members against the other to syn- `clironize said shafts andfor subsequently' shifting one of said positive clutch elements intoengagement with the other, said friction cup clutching member having itsfriction surface threaded, said threads being of suitable pitch andinnumber approximately forty per inch to present a relatively smallfriction surface area capable of substantially instantaneously cuttingthrough the oil lm between the friction surfaces of said members andthereby provide relativelyvhigh unit pressure of engagement of said,friction members affording substantially instantaneous synchronizationof said shafts and minimization of wear of the engaging friction menthaving internal teeth whereby it is splined in encircling relationshipupon the external teeth of said hub, and adapted to be moved axially tobring said teeth into clutching engagement with cooperating jaw clutchteeth on the other member, thus to establish a positive drive connectionbetween said members, a .synchronizeri element driven by said onemember, having an internal friction clutch face, and adapted to be movedaxially into frictional driving engagement with a cooperating clutchface on said other member so as to effect synchronizationfof saidmembers,

l and an annular thrust memberof spring material arranged coaxially withsaid torque-transmitting members, having an axial thrust transmittingconnection with saidsynchronizer element and being biased undercompression in radially outwardly directed yielding engagement with theinner faces of the teeth of said movable clutch element, whereby totransmit axial movement from said movable clutch element to saidsynchronizer element.

30. A transmission' as defined in claim 29, wherein said annular thrustmember is adapted to yield axially with respect to Said movable clutchelement during shifting of the latter, but

remains at all times in engagement with the inber, thus to establish aposltvedrive connection between said members, a synchronizer element'driven by said one member, having an internal friction clutch face, andadapted to be moved axially into frictional driving engagement with acooperating clutch face on said other member so as to eectsynchronization of said members, and a split ring of spring materialarranged coaxially with said torque-transmitting members, having anaxial thrust transmitting connection withsaid synchronizer element andbeing biased under compression in radially outwardly directed yieldingengagement with the inner faces of the teeth of said movable clutchelement, whereby to transmit axial movement from said movable clutchelement to said synchronizer element.

32. A synchronizing transmission as defined in claim 22, wherein the hubis axially xed and the synchronizer ringis axially movable relative tosaid hub.

33. In a synchronizing transmission, a pair of alignedtorque-transmitting shafts, an axially idxed hub 'secured to one of saidshafts, said hub having an axially extending annular depression forminga rim, a jaw clutch element encircling said rim, drivingly connectedthereto, and axially movable` thereon,.a jaw clutch element drivinglyassociated with the other shaft and adapted to be engaged by saidmovable jaw clutch element when the latter is shifted axially, thus toestablish a positive drive connection between said shafts, a frictionclutch element drivingly associated with said other shaft, asynchronizer ring received in the annular depression in the hub, saidring hav-y ing a friction clutch face for coaction with said frictionclutch element, having'a lost motion driving connection with the hub,and including blocking means adapted, inl one of its positionspermittedby said lost motion connection, to block the path of axialshifting movement of said movable clutch element, and, in another ofsuch positions, to allow the movable clutch element to complete itsaxial shifting movement, and means for maintaining said synchronizerelement in constant light frictional engagement with said other frictionclutch element so as to normally maintain said synchronizer elementvbiased in blocking c relation to said movable clutch element, wherebyterior of the teeth of said movable clutch element.

31. In a synchronizing transmission, a pair of torque-transmittingmembers mounted in axial alignment, a hub having external teethmeans formounting said hub on one of said members for rotation therewith butpreventing movement vcooperating jaw clutch teeth on the othermemengagement of the latter with said blocking means during the initialstage of shifting movementserves to transmit axial thrust from themovable clutch element to the synchronizer element for effectingVsynchronization, said last means constituting the sole means forestablishing the blocking relation'.

34. In a synchronizing transmission, a pair of aligned torquetransmitting shafts, an axially iixed hub secured to one of said shafts,said hub having a rim forming an axially opening annular depression, ajaw clutch sleeve encircling ciated with said other shaft, asynchronizer ring,

` partially received infsaid annular depression, havmg a friction dutchface for coaction with saidy `friction clutch element, having a lostmotion -circumferentially osciilatable driving connection with said hub,and including blocking means` adapted, in one of its positions permittedby said lost motion connection, to be engaged by said.

sleeve when the latter is shifted axially soas to j pair of axiallyspaced t movement-said synchronizer ring being arranged to normallymaintain a' constant light frictional engagement with said coactingfriction clutch elementand to be thereby maintained in its blockingposition, said constant light frictional engagement constituting thesole means for insuring the initiationref synchronization under-al1conditions. 1 v

35.l In a synchronizing transmission, a hub, a pair o f axiallyspacedtorque transmitting members between which said hub is mounted inaxial aiignment'therewith, a movable jaw clutch sleeve encircling saidhub, drivingly connected thereto, and axially shiftable thereon intopositive clutching engagement with positive clutch elements drivinglyassociated with the respective torque transmitting members, thereby toestablish a positive drive connectionbetween said hub and either of saidmembers, a pair of synchronizer elements each having alost motiondriving connection with said hub andA including blocking means adaptedin one of its positions permittedvby said lost motion connection, toblock the path oi axial shifting movement of said movable jaw clutchsleeve driving engagement therewith by axial pressure' derived throughthe 'blockingfengagement of'said blocking means and movable jaw clutchsleeve, whereby to effect synchronization between said hub and thecorresponding torque transmitting member, and means for causing thesynchronizer elements to constantly recei've torque from their coactingfriction clutch elements and to thereby be biased in their blockingpositions so as to insure initiation of synchronization, said N meanscomprising an axially yieldable elongated element disposed in the hubandhaving its ends engaged under compression against the respectivesynichronizer elements. .n

3 6. Inia synchronizing` transmission, "a hub, a

-bers between which sai hub is mounted in axial j alignment therewith, fovable :law clutch sleeve encircling 4*said fhub, drivinglyv connectedthereto, 'and axially shiftable thereon 'intopositive clutching iengagement with positive clutch elements drivingly associated .,with therespective torque transmitting members', .thereby -to establish aApositive drive connection between said hub and either of said members,a pair of synchronizer elements each havinga'lost'motion drivingconnection withsaid hub and including blocking means adapted inoneioi'its positions permitted by said lost motion "connection, to'blockthe path o f axial shift-. ing'movement of said movable j aw clutchsleeve -and, in another of such'positiona'to allow the movablejaw'clutch sleevevv to 'complete its wat shifting movement,` saidsynchronizer, elements each having a friction clutch face associatedwith a coacting friction clutch'elemenhdrivingly associated with anadjacent torque transmitting y member and adapted to vbe urged intofrictional driving engagement therewith byaxial pressure derived throughthebiocking engagement of said blocking means and movable jaw clutchsleeve, whereby 'to effect 'synchronization' between said hub and thecorresponding torque transmitting member, and means for causing thesynchronizer i elements to constantly receive torque from their'coacting friction clutch elements and to thereby 5 be biased in theirblocking positions so as to insure initiation of synchronization, saidmeans comp'rising'an axially yieldable elongated element extendingaxiallyof the hub and having its ends engaged under compression againstsaid synchronizer elements.

-37. In a synchronizing mechanism, a shaft, a torque transmitting memberto be synchronized therewith, said member having friction and jaw clutchelements rotating therewith, a hub separate from and mounted upon saidshaft for rotation therewith, said hub having a rim dening :an annulardepression opening axially toward said torque transmitting member, saidrim and said jaw clutch element having allgnable periphl eral teeth, ajaw clutch sleeve encircling said. hub. having internal teeth meshingwith the hub teeth, and shiftable axially into clutching engagement withthe teeth of said positive clutch element, thus to establish a ypositivedrive connecs tion between said shaft and member, a synchronizer ringreceived in said annular depression, having a friction clutch face forcoaction with said friction clutch element, adapted to have limitedrotative movement relative to said hub and including peripheral blockerteeth adapted, in one of its positions of such movement, to be engagedby said internal teeth during shifting movement of the sleeve so as toreceive axial thrustk therefrom and to thereby establish synchronizingfrictional engagement with said friction clutch element, and adapted inanotherof such positions to align with the hub teeth and thereby permitthe sleeve to complete its axially shifting movement, said synchronizerring being arranged to 40 maintain a constant light frictionalengagement '.with'said friction clutch element and to be therebynormally maintained in its blocking position, said constant lightfrictional .engagement constituting the sole means for insuring theinitiation of synchronization under all conditions.

38. In a synchronizing mechanism, a shaft, a torque transmitting memberto be synchronized therewith, said member having friction and jaw clutchelements rotating therewith, a hub separate from and mountedupon saidshaft for rotation therewith, said hub and said jaw clutch elementhaving alignable peripheralteethfa jaw clutch sleeve encircling saidhub,- having internal teeth meshing with the hub teeth and shiftableaxially'into clutching engagement with the teethiof said `iaw 'clutchelement, thus to establish a positive drive connection between said.shaft and member, a synchronizer 4ring conned between said hub andfriction clutch element and having a friction clutch face of smallerdiameter than the pitch diameter of said teeth, for coaction with saidfriction clutch element, adapt- ,d to'have limited rotative movementlrelative to M the hub and including peripheralblocker teeth adapted, inone o f its positions of such movement, to' be engaged by saidinternalteeth during shifting movement of the .sleeve so as to receive i axialthrust therefrom 'and 'to' thereby establish synchronizing frictionalengagement with said friction clutch element. and adapted in another ofsuch positions to align with the hub teeth and thereby permit the sleeveto complete its axially shifting movementpsaid synchronizer ring being yarranged to maintain a constant light frictional -vr engagement .withsaid friction clutch element and CLI

